Caption: Reportage at the Neuroimaging research centre in Pitie Salpetriere hospital in Paris, France. Magnetoencephalography (MEG) platform. MEG detects variations in the brain's magnetic field during various types of cerebral activity. It studies normal and abnormal brain function. Recording the magnetic field produced by neuronal currents requires ultra sensitive sensors called SQUIDs (Superconducting Quantum Interference Device). The 306 sensors spread over 102 areas allow both near and far magnetic fields to be measured, and the brain's deep structures to be 'seen'. The tracks show the real-time recording of the MEG's 306 sensors.